Mamiya 645 - Focusing issues on first rolls. Help?!

[Ian Atherton]

So, after shooting digital for several years, and 35mm film for a year, I decided to graduate to Medium Format recently, and just got my first 5 rolls back from Dwayne's Photo. Most shots are out of focus. Some by a hair, some by a mile. Is there a substantially less margin for error on medium format, or the Mamiya 645? I could really use some help here. Every low light shot came out horrible. Only some of the daytime exposures came out decent. I actually shot these 5 rolls between a standard M645 and a 645 1000S, so I know it's not the camera, and infact user error.

I like to shoot mainly portraits. Would a different focusing screen help here? Or a magnifier of some sort? I used the AE prism as well as the Waist Level winder and achieved poor results with both.

Hoping a MF vet could help.

 

[Ian Grant]

Your using slightly longer FL lenses so less DOF. However it's possible the screens aren't seated properly, would be strange for two different bodies though.

My plain 645 had a slight focus issue compared to my 1000S and needed adjustment, a good repair shop should be able to check it out in a few minutes - it's a simple adjustment, The screens they come with are fine, never gave me a problem (I rarely use my 645's now).

I make GG focus screens on a very regular basis and have some for checking register with MF cameras which hepls enormously, that's how I found the issue with my (plain) Mamiya 645

Welcome to APUG BTW.

Ian

 

[jvo]

welcome to apug...

i use a mamiya pro tl... focus is fine but i do have to pay attention... it doesn't "snap" in like i've had with 35mm. these older eyes require me to be more careful, but no real problem.

 

[Kirks518]

I'll second what jvo said. I shoot a 1000S, and I'm very cautious (slow) when focusing. I do find that the focus screen with the split prism helps tremendously. If you have a plain matte screen, you may want to change it out. The magnifier on the WLF always helps, and there is a magnifier for the M645 prisms as well.

You can also do a focus test, found here: http://bobatkins.com/photography/technical/focus_testing.html

When checking focus on a film camera, you can either burn a roll to check it or what I do is use a ground glass from another camera on the film plane to check it. You can also make a pseudo ground glass with adhesive tape (aka Scotch Tape), which is cheap and easy. I think checking focus accuracy is the only time that digital is better then analog.

 

[Neil Grant]

So, after shooting digital for several years, and 35mm film for a year, I decided to graduate to Medium Format recently, and just got my first 5 rolls back from Dwayne's Photo. Most shots are out of focus. Some by a hair, some by a mile. Is there a substantially less margin for error on medium format, or the Mamiya 645? I could really use some help here. Every low light shot came out horrible. Only some of the daytime exposures came out decent. I actually shot these 5 rolls between a standard M645 and a 645 1000S, so I know it's not the camera, and infact user error.

When I inherited my 645 1000s it had a focus issue. When a lens was set to infinity (and directed to a distant object) the split image rangefinder indicated an 'out-of-focus' condition. The screen sits on three cross-head screws which can be adjusted. Does yours focus to infinity? The split-ilmage screen helps (as long as it's not the diagonal one) - but the camera just isn't that easy to focus - certainly not as easy as a Mamiya RB.

 

[DavidClapp]

However it's possible the screens aren't seated properly...

My 645 1000s had exactly this problem and I only noticed it when cleaning the camera. Infinity was slightly out, enough to mess up all my images. Take the screen out and reseat to see if it makes a difference.

 

[rbultman]

It is not inconceivable that both cameras have issues. I had issues with my Super, but it was due to the mirror stop being broken causing errors in focusing. You can check focus by placing a ground glass or frosted tape on the guide rollers in the film back. Place the camera on a tripod and set the camera for a bulb exposure and the lens to max aperture. First focus using the viewfinder (WLF or prism), then trip and lock the shutter and look at the image on the GG or tape. You might need to use a loupe on the back. The point of focus should be the same.

After finding the issue with the Super, I picked up a Pro in excellent shape. I had been cursing my focus technique but after switching to the Pro, I only have "normal" focus issues due to me wearing glasses or being careless. I use the AE prism finder and I prefer the matte screen to the split image screen for focusing. The matte just works better for me.

Regards,
Rob

 

[gone]

As mentioned, you have to put a ground glass or old focus screen on the film rails and ck infinity w/ a loupe or use a 35mm 50 lens as a loupe. Simply checking to see if the focus screen aligns correctly w/ infinity may or may not work, you need to start w/ the actual image on the GG on the film rails and go from there.

Remember, your DOF on a MF camera is much more shallow than on a 35mm camera. Even more so if you are using longer than normal lenses. Focus accuracy wide open is more critical as there's less room for error. What may have been the eyes a little less than sharp on a 35mm portrait will be totally out of focus on a MF camera if focus is not nailed.

 

[rbultman]

You can also use the "face to face" technique for checking infinity focus. Place a second camera having a known-good focus system in front of the 645, lens to lens. Focus both on infinity. Put the 645 in bulb mode with a GG or tape on the film rails. Use a pencil or erasable marker to place an X on the GG or tape. Look through the second camera. If infinity focus is correct on both cameras, you will see the X clearly.